The cubs are born unformed, and must be licked into shape by the mother

General Attributes

Bears give birth in the winter. The bear cub is born as a shapeless and eyeless lump of flesh, which the mother bear shapes into its proper form by licking it (the origin of the expression "to lick into shape"). The cub is born head first, making its head weak and its arms and legs strong, allowing bears to stand upright. Bears do not mate like other animals; like humans they embrace each other when they copulate. Their desire is aroused in winter. The males do not touch the pregant females, and even when they share the same lair at the time of birth, they lie separated by a trench. When in their fourteen day period of hibernation, bears are so soundly asleep that not even wounds can wake them. Bears eat honey, but can only safely eat the apples of the mandrake if they also eat ants. Bears fight bulls by holding their horns and attacking their sensitive noses. If injured, a bear can heal itself by touching the herb phlome or mullein. The fiercest bears are found in Numibia.

Sources (chronological order)

Pliny the Elder [1st century CE] (Natural History, Book 8, 54): Bears mate at the beginning of winter, after which the male and female retire to separate caves. The cubs are born thirty days later, in a litter of no more than five. Newborn cubs are a shapeless lump of white flesh, with no eyes or hair, though the claws are visible. The mother bear gradually licks her cubs into their proper shape, and keeps them warm by hugging them to her breast and lying on them, just as birds do with their eggs. In the winter, male bears remain in hiding for forty days, and females for four months; during this time they do not eat or drink, and for the first fourteen days are so soundly asleep that not even wounds can wake them. When they emerge from their caves they eat an herb to loosen their bowels and rub their teeth on tree stumps to get their mouths ready. To cure the dimness of their eyes they go to bee hives and allow the bees to sting their faces. A bear's weakest part is the head; some say the brains of bears contain a poison that if drunk drives a man bear-mad. When a bear fights a bull, it hangs from the bull's horns and mouth, and so the weight of the bear tires it. (Book 10, 83): Bears produce young that are unfinished at birth, and shape them by licking them. In this they are like lions and foxes. (Book 11, 115): The breath of bears is pestilential; no wild animal will touch anything a bear has breathed on, and things so tainted quickly go bad.

Isidore of Seville [7th century CE] (Etymologies, Book 12, 2:22): The bear (ursus) has its name because it shapes its young with its mouth, as if begun (orsus). Bear cubs are born as a shapeless lump of flesh; the mother, by licking it, gives it shape. The bear's strength is in its arms and legs, but its head is weak.

Bartholomaeus Anglicus [13th century CE] (De proprietatibus rerum, book 18): Avicenna saith that the bear bringeth forth a piece of flesh imperfect and evil shapen, and the mother licketh the lump, and shapeth the members with licking.... For the whelp is a piece of flesh little more than a mouse, having neither eyes nor ears, and having claws some-deal bourgeoning, and so this lump she licketh, and shapeth a whelp with licking.... And it is wonder to tell a thing, that Theophrastus saith and telleth that bear's flesh sodden that time (of their sleeping) vanisheth if it be laid up, and is no token of meat found in the almery, but a little quantity of humour.... When he is taken he is made blind with a bright basin, and bound with chains, and compelled to play, and tamed with beating; and is an unsteadfast beast, and unstable and uneasy, and goeth therefore all day about the stake, to the which he is strongly tied. He licketh and sucketh his own feet, and hath liking in the juice thereof. He can wonderly sty upon trees unto the highest tops of them, and oft bees gather honey in hollow trees, and the bear findeth honey by smell, and goeth up to the place that the honey is in, and maketh a way into the tree with his claws, and draweth out the honey and eateth it, and cometh oft by custom unto such a place when he is an-hungered. And the hunter taketh heed thereof, and pitcheth full sharp hooks and stakes about the foot of the tree, and hangeth craftily a right heavy hammer or a wedge tofore the open way to the honey. And then the bear cometh and is an-hungered, and the log that hangeth there on high letteth him: and he putteth away the wedge despiteously, but after the removing the wedge falleth again and hitteth him on the ear. And he hath indignation thereof, and putteth away the wedge despiteously and right fiercely, and then the wedge falleth and smiteth him harder than it did before, and he striveth so long with the wedge, until his feeble head doth fail by oft smiting of the wedge, and then he falleth down upon the pricks and stakes, and slayeth himself in that wise. Theophrastus telleth this manner hunting of bears, and learned it of the hunters in the country of Germany. ( Steele edition of 1905)